mangadap.par.emissionlinedb module

Container class for a database of emission-line parameters, as well as support classes and functions.

Class usage examples

To define an emission line:

from mangadap.par.emissionlinedb import EmissionLinePar
p = EmissionLinePar(index=44, name='Ha', restwave=6564.632, action='f', line='l',
                    flux=1.0, vel=0.0, sig=10., mode='f')

More often, however, you will want to define an emission-line database using an SDSS parameter file. To do so, you can use one of the default set of available emission-line databases:

from mangadap.par.emissionlinedb import EmissionLineDB
print(EmissionLineDB.available_databases())
emldb = EmissionLineDB.from_key('ELPMPL9')

The above call uses the from_key() method to define the database using its keyword and the database provided with the MaNGA DAP source distribution. You can also define the database directly for an SDSS-style parameter file:

from mangadap.par.emissionlinedb import EmissionLineDB
emldb = EmissionLineDB('/path/to/emission/line/database/myeml.par')

The above will read the file and set the database keyword to ‘MYEML’ (i.e., the capitalized root name of the *.par file). See Emission-Line Measurements for the format of the parameter file.

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Copyright © 2019, SDSS-IV/MaNGA Pipeline Group

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class mangadap.par.emissionlinedb.EmissionLineDB(parfile)

Bases: SpectralFeatureDB

Basic container class for the database of emission-line parameters.

Each row of the database is parsed using EmissionLinePar. For the format of the input file, see Gaussian Emission-Line Modeling.

The primary instantiation requires the SDSS parameter file with the emission-line data. To instantiate using a keyword, use the from_key() method of the base class; see the base class for instantiation and additional attributes.

key

Database signifying keyword

Type:

str

file

File with the emission-line data

Type:

str

size

Number of emission lines in the database.

Type:

int

_parse_yanny()

Parse the yanny file (provided by file) for the emission-line database.

Returns:

The list of ParSet instances for each line of the database.

Return type:

list

_validate()

channel_names(dicttype=True)

Return a dictionary with the channel names as the dictionary key and the channel number as the dictionary value. If dicttype is False, a list is returned with just the string keys.

default_data_dir = 'emission_lines'

Name of the directory in the mangadap data path with the distributed emission-line databases.

property neml

Number of emission lines in the database.

tie_index_match()

Return an array with the row indices for the tied parameters, which is more useful than the ID number of the tied line.

to_datatable(quiet=False)

Constuct an EmissionLineDefinitionTable instance with the line database.

Parameters:

quiet (bool, optional) – Suppress terminal output

Returns:

Table with the emission-line metadata.

Return type:

EmissionLineDefinitionTable

class mangadap.par.emissionlinedb.EmissionLineDefinitionTable(name_len=1, tie_len=1, shape=None)

Bases: DataTable

A DataTable with the data from an EmissionLineDB object.

Table includes:

Key	Type	Description
ID	int64	Emission line ID number
NAME	str_	Name of the emission line
RESTWAVE	float64	Rest wavelength of the emission line
ACTION	str_	Action to take for this emission line; see Emission-Line “Actions”
TIE_ID	int64	ID of the line to which this one is tied.
TIE_FLUX	str_	Tying parameter for the flux of each line.
TIE_VEL	str_	Tying parameter for the velocity of each line.
TIE_SIG	str_	Tying parameter for the dispersion of each line.

Parameters:

• name_len (int, optional) – The maximum length of any of the emission line names.

• tie_len (int, optional) – The maximum length of a tying string. Not sure if this is needed.

• shape (int, tuple, optional) – The shape of the initial array. If None, the data array will not be instantiated; use init() to initialize the data array after instantiation.

class mangadap.par.emissionlinedb.EmissionLinePar(index=None, name=None, restwave=None, action=None, tie_index=None, tie_par=None, blueside=None, redside=None)

Bases: KeywordParSet

Metadata used to define an emission line for the DAP to fit parametrically.

These parameters are only for a single emission line; see EmissionLineDB for setting a full line list of parameters.

Todo

• Point to/add a description the paramters.

_check()